Homestuck: Sollux gets two. The first is in A 5 A 1, when he withstands the Brown Note of an Eldritch Abomination in order to get Feferi into the Medium. He ends up getting better thanks to having an Extra Life. The second is in [S] Cascade, where he reprises his ancestor's role as the Helmsman and uses all his energy to pilot the troll's meteor to the Green Sun, killing himself in the process. He winds up getting better from that too, in a weird sort of way - Aradia describes him as having "a foot on either side".
AR has a minor one when he keeps blowing up the exiles' stations even as Bec Noir is heading straight for him. Having witnessed his creation, AR has a crippling fear of Becquerel, to the point where he had surrendered to WV earlier for just carrying around a pumpkin with his head carved on it. Noir was about to kill PM as well, until AR distracted him.
Jade's dream self. Jack Noir attacked Prospit and cut the chain which connected it to its moon. As Prospit's moon fell towards Skaia, Jade flew after John's sleeping dream self and attempted to wake him up. When that failed, she threw him and saved him from being crushed by Prospit's moon, dying in the process.
Possibly Tavros. He died in an attempt to fight Vriska, whom he thought was evil at the time (and he was sort of right). Tavros was extremely passive and rarely stood up to anyone, while Vriska was a sadistic God Tier and one of the strongest characters in the comic. Granted, she just stabbed him with his lance before he could even do anything, but still.
It's more than that. Vriska has tormented Tavros for most of his life, and brainwashed him into jumping over a cliff and crippling his legs. Tavros deeply fears her because of this. That scene was the first time he'd attempted to assert himself to her, ever.
This trope seems to be a prerequisite for a Heroic Death, one of two ways a God Tier can die permanently. In fact, John was able to resurrect because his death wasn't awesome enough.
From Schlock Mercenary we get (at the least) Hob's and later Brad's deaths. In both cases they die ensuring that a lot more people won't, thus also making it a CMoH.
Not to mention Tagon-Prime, from the alt-universe, who gets trapped inside an enemy fortress with an Schlock and Elf, both of whom are too injured to be of any help, with the entirety of the galaxy's most famous mercenary force coming after them for revenge after he killed their Captain. To top it all off, his exfilitration has been jammed, and he can't send all three of them back together. So he sends Elf and Schlock, then grabs a gauss pistol and goes down shooting, having taken down 6 mercenaries before being set on fire and shot dead.